1. Field of the Invention
This invention relates to face mask systems for protection from atmospheric pollutants and the supply of oxygen to the mask wearer and more particularly to mask systems to supply oxygen for use in oxygen-depleted environments during aircraft decompression, smoke from onboard fires, airborne debris or other toxic gases which may enter the aircraft flight deck or other crew compartments.
2. Description of Related Art
In the course of aircraft operation, various personnel, including but not limited to pilots, navigation officers, and other flight crew personnel, may need a mask system to provide breathing oxygen and also to provide protection from smoke from onboard fires and other possible airborne eye and lung irritants which may enter the crew compartment(s). There is a requirement in the commercial aviation industry that the masks designed for crew usage be capable of donning in five seconds or less, be able to be donned over eyeglasses and be capable of supplying oxygen consistent with physiological demands at altitudes up to 40,000 feet.
Provisions for stowage of the mask must be sensitive to both the quick-donning requirements and the very limited space and volume available in the aircraft flight decks, and it is particularly desirable that mask storage be compact enough that it is easily placeable within the flight deck in a position close to and convenient to the crewmember when he or she is seated at his or her station. It is also highly desirable that the mask be capable of accommodating a wide variety of facial sizes and configurations while still adequately sealing the face from the external environment.
Since the mask is to be used by crewmembers in an environment that may be highly stressful, both in terms of the visual tasks and the visibility afforded in the presence of smoke and the like, it is important that the mask provide an acceptable level of optical clarity and freedom from distortion consistent with the other desirable characteristics of the mask. Another desirable characteristic is that the mask provide, to the extent possible for a stowable mask, protection from impingement on the face of airborne debris and pollutants, and protection of the eyes in particular from the windborne type of debris that could be present from an explosive decompression or other breach of the windshield system in a large aircraft. Prior art crew masks have addressed these problems with masks incorporating rigid lenses mounted in an otherwise flexible mask, or by combinations of goggles and oxygen masks. While these masks have been functionally useful, they offer disadvantages in field of view, adaptability to a wide range of head sizes and configurations, the ability to be rapidly donned over glasses and stowability in small areas in the cockpit of the aircraft near the crewmember. The present invention provides improved solutions to all of these problems.